KR100379302B1 - Piston top ring - Google Patents

Abstract

It is an object of the present invention to improve the engine output by reducing the amount of blow-by gas, to provide a structure of the engine piston top ring that can prevent oil penetration into the combustion chamber to prevent oil consumption and reduce air pollution.

To this end, the present invention in the piston top ring having a mouth portion, the face of the mouth portion facing each other

Where r is the radius

h: overall height of the ring

g: width of the mouth

Semicircle grooves are formed with an arc of phosphorus radius, and the heights of the upper and lower ends of the semicircle grooves are respectively It is characterized by that.

Description

Piston top ring for engines

The present invention relates to a structural improvement of an engine piston top ring for blow-by gas generation and engine oil consumption.

The head of the piston receives the same high temperature as the cylinder that forms part of the combustion chamber, but its expansion ratio is larger than that of the cylinder because it cannot be directly cooled by coolant or outside air, and the design dimension of the piston considers such expansion due to the difference in temperature. The diameter of the head portion is smaller than that of the cut portion so that a clearance is provided, and a piston ring is attached to the head portion to prevent the compressed gas from leaking through the clearance (clearance).

This piston ring keeps the combustion chamber tight against compression and expansion gas pressure and prevents the expansion gas from leaking from the combustion chamber into the crankcase, while transferring most of the heat the piston receives to the cylinder wall and oil sprayed on the cylinder wall. The open opening on one side of the circle is required to provide the minimum amount of oil required to scrape off and at the same time provide adequate resilience to the cylinder bore to provide a tight contact with the cylinder bore to prevent the remaining oil from entering and entering the combustion chamber. It is formed of a ring of steel or steel and fitted to the piston ring groove.

On the other hand, the piston ring is provided with an end gap that cuts a portion of the ring to generate tension in order to be fitted to the groove of the expansion and piston ring, the compressed gas leaks through Bigas), and serves as a passage for the engine oil to enter the combustion chamber.

As such, the presence of the inlet portion is closely related to the consumption of engine oil. Due to the inlet portion, a pressure difference is generated between the upper and lower portions of the piston top ring (the first and second land portions).

However, if the pressure of the second land portion (between the piston top ring and the piston second ring) is high, a section in which the up and down pressure of the top ring is reversed appears after the rear end of the expansion stroke, thereby causing the piston top ring to move up and down to induce oil consumption. There is a problem.

In order to solve this problem, it is necessary to keep the size of the inlet of the piston top ring small and the size of the inlet of the piston second ring large so as to keep the pressure of the second land portion high. It is necessary to reduce the pressure by increasing the flow rate through the inlet portion of the piston second ring and increasing the volume of the second land portion.

For this reason, as shown in Fig. 4, in order to reduce the consumption of the blow-by gas amount and the amount of engine oil, piston rings 14, 15 having various inlet portions 10, 11, 12, 13 are formed. 16) and 17 are used.

However, the piston ring and the like having various inlet parts of the above-described shape is complicated in processing, and the unit cost increases, and the heat stress is concentrated on the protruding portion, so that the strength is weak and the flow rate through the inlet is reduced. It is pointed out that the problem is difficult.

Accordingly, the present invention has been proposed in view of the above, and its object is to reduce the amount of blow-by gas to improve engine output, and prevent engine oil penetration into the combustion chamber to prevent oil consumption and reduce air pollution. To provide a structure.

In order to achieve the above object, the present invention is characterized in that in the piston top ring having the inlet portion, grooves of any shape are formed on surfaces facing each other of the inlet portion.

1 is a perspective view showing the fitting portion of the engine piston ring according to the present invention

Figure 2 is a front view showing the fitting portion of the engine piston ring according to the present invention

3 is a model diagram for calculating the flow rate through the mouth of the piston top ring

4 is a structure of a general piston top ring

※ Explanation of codes for main parts of drawing

1: piston top ring 2: mouth

3,4 semicircular groove g

h: Overall thickness of piston ring h ₁ (½g): Upper thickness (height)

h ₂ (½g): Lower thickness (height)

Hereinafter, the configuration and operation of the present invention will be described with reference to the accompanying drawings.

1 is a perspective view showing the structure of the inlet portion of the piston top ring according to the present invention, FIG. 2 is a front view of the in-phase inlet portion, and FIG. 3 is a flow rate calculation model passing through the inlet portion.

The mouth port 2 of the piston ring 1 of the present invention has a width g and a height (same as the entire height of the piston ring) is h.

Radius is provided on the surfaces of the piston ring 1 and the inlet portion 2 that face each other. In the groove, in the illustrated embodiment, semicircular grooves 3 and 4 are formed, and on the upper and lower sides of the semicircular grooves 3 and 4, respectively. It is formed by the height h ₁ (h ₂ ) of (corresponding to the thickness up to the top and bottom ends).

Pressure of the second land portion 5 in FIG. 3 silver

Q ₁ = Flow rate through the inlet of the piston top ring

Q ₂ = Flow rate through the inlet of the piston second ring

V ₁ = volume of clearance formed between the second land portion and the piston

T ₂ = temperature of the second land portion

if If you are in a subsonic state

Become,

if Supersonic

If it is

However, A: area of the pit

Cd: Transmission Factor

: Specific heat ratio of air (1.4)

R: Gas constant of air

P ₁ : combustion chamber pressure

T ₁ : combustion chamber temperature

Becomes

Here, when the pressure in the combustion chamber and the pressure difference (P ₁ -P ₂ ) of the second land portion is not large, the flow rate passing through the inlet of the piston ring is determined as in Equation (1), and the pressure difference (P ₁ -P). _{If 2} ) is very large, the flow rate through the inlet is indicative of supersonic flow. By the way, the flow rate transmission coefficient at the inlet portion is greatly influenced by the shape of the inlet portion, the discharge coefficient (Cd) has a maximum value in the section between the shape ratio (h / g) of about 1 to 2.

Therefore, it is important to reduce the aspect ratio (h / g) in order to reduce the transmission coefficient (Cd), the present invention is configured as shown in Figure 1, lowering the transmission coefficient.

That is, when configured as in the present invention, the aspect ratio The oil passes through two narrow passages of 0.5 so that the flow rate Q ₁ passing through the inlet 2 is reduced, and the flow resistance through the passage of one neck through the two narrow passages This increases and Q ₁ decreases.

On the other hand, when the pressure difference (P ₁ -P ₂ ) of the piston top ring (1) upstream and downstream of the mouth ( ₂ ) is large, so that the supersonic flow flows, the existing ring and the ring of the present invention, or both, according to the cross-sectional area of the inlet and the pressure and temperature of the combustion chamber Since this is determined, both will have the same flow rate.

Therefore, the flow rate Q ₁ passing through the inlet portion 2 of the piston top ring in the entire operating region of the engine is smaller in the ring structure as in the present invention, and when the passage flow rate is small, the pressure P ₂ of the second land portion is also reduced. The lower the piston top ring (1) is to move up and down in the ring groove to reduce the oil penetration into the combustion chamber.

Here, the shape of the grooves 3 and 4 may be not only semicircular but also rectangular, square and triangular.

According to the present invention as described above by changing the shape of the inlet portion of the piston top ring to allow the flow rate to pass through the two narrow passages having a low aspect ratio, the vertical movement of the piston top ring is reduced to prevent oil penetration into the combustion chamber to prevent oil consumption and There is an effect to greatly reduce the exhaust gas generation, and also has the effect of reducing the blow-by gas generation amount.

Claims (5)

In the piston top ring with the inlet, To form a groove of any shape on the surface facing each other of the fitting portion, The height (h ₁ , h ₂ ) of the upper and lower ends of the groove are each 1/2 g piston top ring. Where h ₁ : height at the top h ₂ : height of the bottom g: width of the mouth delete The method of claim 1, The piston top ring of the engine, characterized in that at least the height h ₁ of the upper end of the groove. The method of claim 1, The piston top ring of the engine, characterized in that at least the height h ₂ of the bottom of the groove is 1 / 2g. The method according to claim 1 or 3 or 4, Wherein the groove is a piston top ring of the engine, characterized in that any one of the groove selected from rectangular, square, triangular and semi-circular.